Hobby service having enhanced operational performance

ABSTRACT

An apparatus is disclosed for enhancing the operational performance of a servo. The apparatus comprises an auxiliary shaft that is independent and displaced from the servo and an actuation sensor that is operably coupled to the auxiliary shaft. The auxiliary shaft is configured to be driven by a motor associated with the servo.

The present application is a continuation of, and is based on, andclaims the benefit of U.S. patent application Ser. No. 11/153,800, filedon Jun. 15, 2005, the content of which is hereby incorporated byreference in its entirety, the latter application being based on U.S.provisional application 60/584,288, filed on Jun. 30, 2004.

BACKGROUND

The present invention generally pertains to the hobby-mechanicalindustry. More specifically, the present invention pertains to means forextending the torque and/or rotational capacity of a hobby servo.

A servo motor (a.k.a. simply a “servo”) is a device having a rotatableoutput shaft. The output shaft can typically be positioned to specificangular positions in accordance with a coded signal received by theservo. It is common that a particular angular position will bemaintained as long as a corresponding coded signal exists on an inputline. If the coded signal changes, the angular position of the shaftwill change accordingly. Control circuits and a potentiometer aretypically included within the servo motor casing and are functionallyconnected to the output shaft. Through the potentiometer (e.g., avariable resistor), the control circuitry is able to monitor the angleof the output shaft. If the shaft is at the correct angle, the motoractuates no further changes. If the shaft is not at the correct angle,the motor is actuated in an appropriate direction until the angle iscorrect.

There are different types of servo motors that include output shaftshaving varying rotational and torque capabilities. For example, therotational and/or torque capability of an industrial servo is typicallyless restricted than that of a hobby servo. That being said, hobbyservos are generally available commercially at a cost that is much lessthan that associated with industrial servos.

Because hobby servos are relatively small and inexpensive, they arepopular within the hobby-mechanical industry for applications such as,but by no means limited to, hobby robotic applications andradio-controlled models (cars, planes, boats, etc.). One example of ahobby servo is the Futaba S-148 available from Futaba Corporation ofAmerica located in Schaumburg, Ill.

The output shaft of a hobby servo is typically capable of travelingapproximately 180° (possibly up to 210° or more depending onmanufacturer). Rotation of the hobby servo shaft is limited typically byone or more internal mechanical stops. It is also typically true thatthe output shaft of a hobby servo is capable of producing a relativelylimited amount of torque power. The torque and rotational limitations ofa hobby servo are adequate for many hobby applications, such as modelcar steering control, puppet control, robot arm or head movement and/ormodel airplane rudder control. It is true, however, that someapplications require a servo having torque power and/or a rotationalcapacity that is beyond the capability of a typical hobby servo.Increased torque power and/or rotational capacity enable greatermechanical flexibility.

Some hobby servos can be mechanically altered to provide an extendedrange of rotation. However, this solution requires mechanical alterationthat often only works for some types of servos. Rotational control formost hobby servos is limited by the internal potentiometer beingutilized to monitor rotation. When a hobby servo is hacked to extend therotational capacity, the internal potentiometer of the servo will, inmost instances, not be configured to monitor angular positions too farbeyond the original range of rotation. The control system of a hackedservo will commonly not be configured to accurately position the servooutput shaft too far within the extended range of rotation. For thisreason, it becomes difficult to control rotation once a hobby servo hasbeen adapted for extended rotation.

SUMMARY

Embodiments of an independent and modular apparatus are disclosed forenhancing the operational performance of a servo motor. Embodimentsinclude a frame member having a servo motor and a rotatable shaftmounted therein. The output shaft of the servo motor and the rotatableshaft are displaced from one another. Means are incorporated fortranslating rotational motion from the output shaft to the rotatableshaft so as to enable a torque or rotational capacity for the rotatableshaft that is greater than that of the servo output shaft. Further meansare incorporated to enable proportional control of the rotatable shafteven when the output shaft of the servo is rotated beyond its intendedrange of rotation and/or torque.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a hobby servo.

FIG. 2 is a side and front view of an enhancement gear.

FIG. 3 is a side view of the enhancement gear after being engaged to thehobby servo.

FIG. 4 is a top perspective view of an enhancement sprocket.

FIG. 5 is a top perspective view of an apparatus for extending thetorque capacity of a hobby servo motor.

FIG. 6 is a top perspective view of an apparatus for extending therotational capacity of a hobby servo motor.

FIG. 7 is a side perspective view of an apparatus for extending therotational capacity of a hobby servo motor.

FIG. 8A is a front perspective view of an apparatus for extending theoperational capacity of a servo motor.

FIG. 8B is a back perspective view of the apparatus of FIG. 8A.

FIGS. 9A-9K are diagrammatic illustrations demonstrating alteration of ahobby servo motor.

FIGS. 10A, 10B, 11, and 12A-12K are diagrammatic illustrationsdemonstrating construction of an apparatus for extending the operationalcapacity of a servo motor.

DETAILED DESCRIPTION

FIG. 1 is a side view of a hobby servo 100. Servo 100 includesattachment flanges 104. Flanges 104 typically include apertures formedtherein for receiving an attachment mechanism (e.g., a screw, bolt,etc). The attachment mechanism is utilized to secure servo 100 within anoperative environment. Servo 100 also includes an electrical connection106 that enables the servo to receive electrical power and/or controlsignals.

Servo 100 includes a rotatable output shaft 102 also known as a servospline. The servo output shaft 102 can be positioned to specific angularpositions in accordance with a coded signal received by the servo. It iscommon that a particular angular position will be maintained as long asa corresponding coded signal exists on an input line. If the codedsignal changes, the angular position of the servo output shaft 102 willchange accordingly. Control circuits and a potentiometer are typicallyincluded within the illustrated outer housing of servo motor 100. Thecontrol circuits and potentiometer are functionally connected to theservo output shaft 102. Through the potentiometer (e.g., a variableresistor), the control circuitry is able to monitor the angle of theoutput shaft. If the shaft is at the correct angle, the motor actuatesno further changes. If the shaft is not at the correct angle, the motoris actuated in an appropriate direction until the angle is correct.

Rotation of servo output shaft 102 is typically limited to around 180°.In most cases, rotation is limited at least because of an internalmechanical stop. It is also common that servo output shaft 102 iscapable of producing a relatively limited amount of torque power. Thetorque and rotational limitations of a hobby servo are adequate for manyapplications; however, some applications require a servo having torquepower and/or a rotational capacity that is beyond the capability of atypical hobby servo. Increased torque power and/or rotational capacityenable greater mechanical flexibility.

FIG. 2, in accordance with one aspect of the present invention, is aside and front view of a servo enhancement gear 150. Servo gear 150includes a plurality of gear teeth 152 disposed around an outer edgeperimeter of gear 150. A female spline receiver 154 is formed throughthe approximate middle of the gear. Spline receiver 154 is,illustratively, an aperture having a series of teeth formed around theouter perimeter. The teeth formed within spline receiver 154 areillustratively configured to engage a corresponding set of teeth formedon servo spline 102. It is common for servo spline 102 to have a 23, 24or 25 tooth configuration. In accordance with one aspect of the presentinvention, a different gear 150 can be utilized depending upon whichspline receiver 154 configuration is needed to accommodate a givenspline 102. In accordance with another embodiment, a specialized splinereceiver 154 configuration for a gear 150 is configured to accommodateattachment to multiple spline 102 configurations. It should be notedthat spline receiver 154 configurations other than those suitable for23, 24 or 25 tooth configurations are within the scope of the presentinvention.

FIG. 3, in accordance with one aspect of the present invention, is anillustration of a servo enhancement gear 150 that has been attached to aservo 100. Spline receiver 154 is engaged to spline 102. A washer 158and a screw 160 are utilized to secure gear 150 to spline 102. In oneembodiment, washer 158 has an overall diameter that is greater thanspline receiver 154. Accordingly, the washer is centered on the outsideface of gear 150 such that the aperture in the washer corresponds to anattachment aperture formed in spline 102. Screw 160 is then engaged intothe attachment aperture in spline 102 until washer 158 tightens againstgear 150 thereby locking gear 150 into a rotational engagement withspline 102. Of course, other attachment schemes are within the scope ofthe present invention.

In accordance with one aspect of the present invention, gear 150 isconfigured such that the surface around spline receiver 154 will engagea surface proximate spline 102 in a flush manner. For example, withreference to FIG. 1, servo 100 includes a relatively planar surface 108.Similarly, with reference to FIG. 2, gear 150 includes a relativelyplanar surface 156. As is shown in FIG. 3, when gear 150 is engaged toservo 100, surfaces 108 and 156 are engaged to one another in arelatively flush relationship.

In accordance with one aspect of the present invention, a rotationalmechanism other than a gear is attached to servo spline 102 in a mannersubstantially similar to the attachment scheme shown and described inrelation to FIGS. 1-3. FIG. 4 is a perspective view of a sprocket 400.Sprocket 400 includes a plurality of teeth 452 disposed around an outerperimeter of sprocket 400. A chain 456 is in engagement with asubstantial number of teeth 452. A hub 458 is located within the centerof sprocket 400 and is supported by a plurality of spokes 460. Hub 458includes a spline receiver 454. Spline receiver 454 is illustrativelysimilar to spline receiver 154 (FIG. 2) in that it is configured toengage a standard hobby servo output spline 102 (FIG. 1). Differentversions of sprocket 400 can be selected and/or created to accommodatedifferent servo splines 102. A sprocket 400 having a spline receiver 454configured to receive a 23, 24, 25 tooth or any other output splineconfiguration is within the scope of the present invention.

Engagement of a sprocket 400 to a servo motor 100 is illustrativelysimilar to the engagement schemes described in relation to FIGS. 1-3.Spline receiver 454 is engaged to spline 102. In accordance with oneembodiment, a washer/screw arrangement is utilized to secure thesprocket to the servo as was previously described. In accordance withanother embodiment, however, the outside portion of hub 458 (oppositethe side where the servo spline is inserted) is configured such that thespline receiver 154 aperture is closed but for an opening large enoughfor insertion of an attachment mechanism (i.e., a screw). In this case,a washer is not necessary because a screw can be inserted through theaperture and into the engagement with the servo spline 102. As a screwis tightened into engagement with the servo spline 102, the head of thescrew will engage the sprocket hub and secure the sprocket to the servo(i.e., secure the servo spline within hub 458).

In accordance with one aspect of the present invention, hub 458 ofsprocket 400 is configured such that a surface of the sprocket willflushly engage a surface of the servo motor when the motor and sprocketare functionally engaged to one another. As is shown in FIG. 4, anannular lip 480 is formed on the inside of hub 458 to enable a flushengagement with surface 108 illustrated in FIG. 1.

In accordance with one aspect of the present invention, any rotationaldevice can be attached to a servo output shaft in a manner as describedherein in the context of a gear and a sprocket. Once attached to theservo output shaft, the item will generally rotate when the output shaftrotates. Accordingly, the rotation of the item will be limited just asis the rotation of the output shaft.

As was mentioned above, some mechanical applications require a servohaving a range of rotation greater than the range typically associatedwith a hobby servo. Also, some mechanical applications require a servohaving greater torque power than that typically associated with a hobbyservo. The present invention pertains to simple and inexpensiveenhancements for hobby servos that are capable of enabling a greaterrange of rotation, or a greater range of torque power, than typicallyassociated with a hobby servo without sacrificing proportional controlcharacteristics.

Accordingly, a gear, sprocket or any other rotational mechanism can besecured to the output shaft of a hobby servo. In accordance with oneaspect of the present invention, the hobby servo can then be mounted ina frame and configured to translate rotational motion to a shaft that isrotatably mounted within the same frame. The shaft will then beconfigured for a torque and/or rotational capacity that is greater thanthe output shaft of the servo itself.

FIG. 5 is a perspective view of an apparatus 500 for extending theoperational capacity of a servo motor 502. Servo 502 is secured withinframe 504. For example, frame 504 illustratively includes aperturesformed therein and configured to receive an attachment mechanism (e.g.,a screw, bolt, etc). In one embodiment, apertures formed in frame 504are configured to line up with apertures formed in attachment flanges104 (FIG. 1). An attachment mechanism can then be inserted through theapertures in flanges 104 that are lined up with corresponding aperturesin frame 504. In this way, the servo can be secured to the frame. WithinFIG. 5, screws 522 are illustrated. These screws illustratively areinserted through apertures in a flange 104, and through correspondingapertures formed in the frame. A bolt can then be engaged to the ends ofthe screws 522 so as to secure a flange 104 to the frame 504. A gear 550is attached to the output spline of servo motor 502 with a screw 160 anda washer 158 as described in relation to FIGS. 1-3 (another attachmentscheme such as the non-washer scheme described in relation to sprocket400 in FIG. 4 could alternatively be utilized). Gear 550 isillustratively similar to gear 150 (FIG. 2) only smaller. Servo 502 isillustratively similar to servo 100. The servo output shaftillustratively has a limited capacity for rotation (e.g., around 180°).

An auxiliary shaft 542 is rotatably mounted in frame 504 and isdisplaced from servo 502. An auxiliary gear 544 is attached to auxiliaryshaft 542 and engaged via gear teeth to gear 550. Again, gear 550 isattached to the output shaft of servo 502. Accordingly, when the outputshaft of servo 502 is caused to rotate, gear 550 causes that rotation tobe translated to auxiliary gear 544, and therefore to auxiliary shaft542. Because gear 550 is considerably smaller than auxiliary gear 544,the torque associated with auxiliary shaft 542 will be much greater thanthe torque of the servo motor output shaft. The expanded torqueassociated with shaft 542 can then be configured to actuate a mechanicalload. For example, an item can be attached to auxiliary shaft 542 (orattached to gear 544) and utilized to mechanically take advantage of theexpanded torque.

In accordance with another embodiment, auxiliary gear 544 has a diameterthat is much less than the diameter of gear 550. Accordingly, when gear550 is attached to a hobby servo output shaft, and when gear 544 isattached to an auxiliary shaft, then auxiliary shaft 542 will produce arange of rotation that is greater than that generated by the outputshaft of the hobby servo.

FIG. 6 is a top perspective view of an apparatus 600 for extending theoperational capacity of a servo motor. FIG. 6 shows a hobby servo 602mounted within a frame 604. Servo 602 is illustratively similar to servo502. Similar to the FIG. 5 configuration, auxiliary shaft 642 isrotatably mounted within frame 604 and is displaced from hobby servo602. A chain 656 is engaged to teeth 652 of an enhancement sprocket 650.An auxiliary gear 644 is attached to auxiliary shaft 642.Illustratively, enhancement sprocket 650 can be attached to the outputshaft of hobby servo 602 as was described in relation to FIG. 4. Chain656 illustratively stays engaged to teeth 652 while chain 656 becomesengaged to auxiliary gear 644. Accordingly, when the output shaft ofhobby servo 602 is caused to rotate, chain 656 causes that rotation tobe translated to auxiliary gear 644 and therefore to auxiliary shaft642. Because enhancement sprocket 650 is considerably larger thanauxiliary sprocket 644, the rotation of auxiliary shaft 642 will be muchgreater than the rotation of the output shaft of hobby servo 602 andmuch greater than the overall rotation of enhancement sprocket 650. Theexpanded rotation of auxiliary shaft 642 can then be configured toactuate a mechanical load. For example, a mechanical item can beattached to auxiliary shaft 642 and utilized to mechanically takeadvantage of the expanded rotational motion.

In accordance with one embodiment, enhancement sprocket 650 has adiameter that is much less than the diameter of the correspondingauxiliary gear 644. Accordingly, when enhancement sprocket 650 isattached to a hobby servo output shaft, and when auxiliary gear 644 isattached to an auxiliary shaft, and when chain 656 is in place, thenauxiliary shaft 642 will produce a torque power that is greater thanthat generated by the output shaft of the hobby servo.

In accordance with another embodiment, a belt design can be utilizedrather than a chain design. For example, enhancement sprocket 650 andauxiliary gear 644 can be configured to accommodate a belt rather than achain. Accordingly, as the output shaft rotates and causes enhancementsprocket 650 to rotate, a frictionally engaged belt moves around theoutside diameter of the enhancement sprocket as well as around theoutside diameter of the auxiliary gear, such that rotational motion istranslated from the output shaft to the auxiliary shaft. When a belt isutilized, enhancement sprocket 650 and auxiliary gear 644 need notnecessarily have gear teeth.

As was described in relation to FIG. 5, in accordance with anotheraspect of the present invention, neither a belt nor a chain is utilized.Instead, enhancement sprocket 650 and auxiliary gear 644 are directlygeared to one another. The enhancement sprocket 650 is secured to theoutput shaft of the hobby servo 602 as discussed in relation to FIGS.1-3. The enhancement sprocket 650 is directly and operably engaged toauxiliary gear 644. Auxiliary gear 644 is configured to translaterotational motion to auxiliary shaft 642.

FIG. 7 is a side perspective view of the apparatus 600 previouslyillustrated and described in relation to FIG. 6. The view shown in FIG.7 demonstrates how frame 604 is constructed. Frame 604 includesapertures 730 for receiving an attachment mechanism (e.g., a screw,bolt, etc) for attaching apparatus 600 within an operationalenvironment. For example, the frame could be secured in a locationproximate to a target for mechanical actuation. The frame memberincludes a first aperture 732 for receiving and supporting servo 602. Asecond aperture 722 is also formed in the frame and is configured toreceive and support auxiliary shaft 642.

Attachment apertures 740 are formed in the frame as necessary toaccommodate attachment of servo 602 to the frame (e.g., attachmentflanges associated with the servo have apertures that are lined up withthe attachment apertures 740 within the frame . . . and an attachmentmechanism is slid through the aligned apertures to secure the servo tothe frame).

Frame 604 includes a first panel portion 734 that is displaced from butconnected to a second panel portion 736. A displacement mechanism 738 ispositioned between panels 734 and 736. In fact, several displacementportions 738 are utilized to space and support the panel portionsrelative to one another. Each displacement mechanism 738 isillustratively attached to the first and second panel portions. Forexample, an attachment mechanism (e.g., a screw, an adhesive, etc) isutilized to secure the displacement mechanisms 738 between the panelportions. In one embodiment, a screw is inserted through an aperture ina panel portion and into the displacement portion 738. The screw canextend all the way through the displacement portion 738 and through acorresponding aperture formed in the opposite panel portion, wherein abolt is then utilized to secure the panel portions to the displacementmechanism. Alternatively, a single screw can be inserted through eachend of the displacement mechanism through an aperture formed in thepanel portion such that the screws engage and secure themselves to theinside of the displacement portion thereby securing the panel portionsto the displacement portion.

FIGS. 8A and 8B, in accordance with one aspect of the present invention,are front and back views, respectively, of a different apparatus 800 forextending the operational capacity of a servo motor. Apparatus 800 issimilar in many aspects to embodiments previously illustrated anddescribed herein. Hobby servo 802 and auxiliary shaft 842 are mountedwithin frame 804. Auxiliary gear 844 is attached to auxiliary shaft 842and is rotatably coupled to servo motor gear 850 in a manner similar tothat illustrated in FIGS. 3-6. For example, means such as a directedengagement, shown in FIG. 5, or a chain, shown in FIGS. 4 and 6, or anyother means may be used to translate rotation from the servo outputshaft to auxiliary gear 844 and shaft 842. In accordance with theillustrated embodiment, apparatus 800 is configured in a torqueenhancement configuration (an enhanced rotation configuration mayalternatively be implemented). In the illustrated configuration, gear850 has a diameter much less than the diameter of auxiliary gear 844. Asa result, the torque capacity associated with auxiliary shaft 842 willbe greater than the torque capacity of the servo motor gear 850. Theexpanded torque capacity associated with shaft 842 can be takenadvantage of to actuate increased mechanical loads. For example, an itemcan be attached to auxiliary shaft 842 (or to gear 844) and utilized tomechanically take advantage of the expanded torque capacity.

Another result of the illustrated configuration, however, is thatauxiliary gear 844 will have an angular rotational range which is evenless than the standard angular rotational range of hobby servo gear 850.Most hobby servos have a predetermined rotational range of approximately180°. The illustrated auxiliary gear 844 will have a rotational range ofeven less than 180°. For certain applications, expanded torque is neededwithout sacrificing rotational range.

In accordance with another aspect of the present invention, hobby servo802 is internally modified to enable a range of output shaft rotationthat is greater than its “off-the-shelf” capability. For example, inaccordance with one embodiment, an internal mechanical stoppingmechanism, which prevents rotation past a predetermined angle, isremoved from hobby servo 802 to enable for continuous rotation in eitherdirection. As a result of the modification, servo 802 can rotateauxiliary gear 844 beyond the range of rotation attributed to the gearprior to the servo modification.

Following modification of servo 802, limitations inherent to theinternal potentiometer make it a poor choice for subsequent controlfunctionality. As previously mentioned, in a normal servo operatingconfiguration, the servo motor rotates the servo output shaftcorresponding to the coded signal received by the servo. The outputshaft is rotated until the signal from the internal potentiometer of theservo, which corresponds to the angular position of the servo outputshaft, matches the coded signal received by the servo. Most hobby servoscontain internal potentiometers that are physically limited tomonitoring a limited range of angles (e.g., often less than 200degrees). Therefore, when apparatus 800 is configured in the illustratedenhanced torque configuration and incorporates a servo 802 modified forextended rotation, the internal potentiometer is not the best controlcomponent for applications that require the servo shaft to rotate beyondthe typical rotation limits in order to provide shaft 842 with animproved rotational capacity. The internal potentiometer is not likelyto support control of a range of rotation for shaft 842 that is evenequivalent to the original rotational range of the servo output shaft.Therefore, in accordance with one aspect of the present invention, theinternal potentiometer is disconnected and an auxiliary potentiometer880 is asserted into the control scheme. Potentiometer 880 isfunctionally connected to shaft 842 and facilitates the proportionalcontrol thereof.

Accordingly, as was mentioned above, some applications require increased(enhanced) torque while still demanding the same, or in some casesgreater, rotational capacity. Therefore, in accordance with one aspectof the present invention, the external potentiometer 880 is attached toauxiliary shaft 842 and is utilized to control the rotation of auxiliaryshaft 842. As a result, servo 802 utilizes the coded input signal andthe signal from external potentiometer 880 to rotate and positionauxiliary shaft 842. A particular external potentiometer 880 having anyof a variety of control characteristics can be selected and implementedbased on the requirements of a given application. Therefore, apotentiometer with a rotational range of substantially less than orgreater than 180° can be selected and implemented as desired.

In accordance with one embodiment, apparatus 800 is configured in anextended rotation configuration. In this configuration, as previouslymentioned, servo gear 850 has a diameter substantially greater thanauxiliary gear 844. Further, in accordance with this embodiment,external potentiometer 880 is configured to provide rotational and/orposition control over the extended range of rotation of auxiliary shaft842.

In accordance with one aspect of the present invention, FIGS. 9A-9K arediagrammatic illustrations demonstrating alteration of a hobby servoincluding removal of rotation impediments and disconnection of theinternal potentiometer. While many types and brands of hobby servos canbe modified in a manner similar to the processes described herein, FIGS.9A-9K are directed to the removal of mechanical stops from a HitecHS-645MG hobby servo available from Hitec RCD USA, Inc. located inPoway, Calif.

In accordance with FIG. 9A, screws are removed from the bottom of theservo 802 and the top gear case (not pictured) is removed to expose thedrive gears. The second to last drive gear 910 is removed first,followed by the main spline (gear with shaft) gear 912 as illustrated inFIG. 9B. Further, the bushing or bearing 914 is removed from the splinegear 912 (also as pictured in FIG. 9B). Not all servos have a bushing orbearing. In some cases, the outer gear case cover is configured to serveas a bushing. The bottom case (not pictured) is removed from the servo802 and the electronics 916 and the potentiometer 918 are removed asillustrated in FIG. 9C. With the spline gear 912 out, pliers are used toremove the small pin stop 920 as shown in FIG. 9D (care must beexercised as to not damage the teeth on the gear). A utility knife isused to trim the case (make a groove 922) as illustrated in FIG. 9E toallow for extra wires that will be required to enter into the case whenan auxiliary potentiometer is subsequently installed.

Wires 924 are disconnected from the internal potentiometer 918 using asoldering iron, while making note of the position of each colored wire924 as different servos incorporate different colors and configurations(i.e. white=left, yellow=center, red=right) (shown in FIG. 9F). Theelectronics 916 and potentiometer 918 are put back in the case 908,illustrated in FIG. 9G, with the potentiometer wires 924 running throughthe groove 922 (created by the step shown in FIG. 9E). The bottom case906 is replaced to cover the electronics 916 (FIG. 9H) and the gears arereassembled back in place (FIG. 9I). The bearing or bushing 914 isplaced back on the main spline gear 912 and the top gear case 904 isplaced back on the servo (FIG. 9J). The screws are replaced in thebottom of the servo and the pinion gear 950 is mounted onto the servooutput shaft using a washer 952 and servo horn screw 954 (FIG. 9K).Pinion gear 950 is functionally similar to servo output gear 850referenced to apparatus 800 in FIG. 8.

In accordance with one aspect of the present invention, FIGS. 10A, 10B,11, and 12A-12K are diagrammatic illustrations demonstrating theconstruction of apparatus 800 and the connection of externalpotentiometer 880. FIG. 10A is a diagrammatic illustration demonstratingan illustrative layout of a top mounting plate 876 of apparatus 800.Plate 876 has a length 1014 of 3.907″ and a width 1016 of 2.280″.Distances 1010, 1012, and 1018 between mounting holes is 1.750″, 1.457″,and 1.780″, respectively. A bottom mounting plate 878 of apparatus 800,represented in FIG. 10B, has a length 1020 of 3.447″ and a width 1022 of1.280″. FIG. 11 is further directed to the configuration and layout ofapparatus 800. Apparatus 800 has an overall length 1014 of 3.907″ andheight 1026 of 2.5″. Distance 1024 between the edges of potentiometer880 and servo 802 is 3.008″. Distance 1028 from the edges of topmounting plate 876 and bottom mounting plate 878 is 1.12″. Also,distance 1030 from the top edge of auxiliary shaft 842 to the bottom ofservo 802 is 2.235″.

It should be noted that all measurements provided herein are providedfor the purpose of giving a complete description only. The presentinvention is not so limited. Other measurements are certainly within thescope of the present invention. It should also be noted that throughoutthe present description, preference numerals that are the same withinmultiple figures are intended to designate features that are the same orsimilar to another.

FIG. 12A illustrates a disassembled apparatus 800 including externalpotentiometer 880, top mounting plate 876, bottom mounting plate 878,brass bushing 882, servo pinion gear 884, large spur gear 886, washer888, hub 890, hub mounting screws 892, servo mounting screws 894, shortstandoff posts 896, and standoff mounting screws 898. Modified servo 802(with mechanical stops removed and potentiometer wires disconnected(illustrated in FIGS. 9A-9K) is not shown. FIG. 12B illustrates boltingexternal potentiometer 880 to bottom mounting plate 878. Brass bushing882 is inserted into the hole contained in top mounting plate 876,making sure that the bushing is flush with the surface of the plate(FIG. 12C). Next, with the bushing flange facing upward, the four servomounting screws 894 are used to mount modified servo 802 to top mountingplate 876 as shown in FIG. 12D. The bolts should not be over-tightenedas they need to be loose to properly mesh the gears later. Further, thestandoff posts 896 are mounted using the standoff screws 898 andhand-tightened as illustrated in FIG. 12E. FIG. 12F illustrates mountingbottom plate 878 to top plate 876 by pushing the output shaft ofpotentiometer 880 through the front plate and using standoff screws 898to secure both plates to the standoff posts 896. Hub 890 is mounted tolarge spur gear 886 using hub mounting screws 892 (FIG. 12G). Large spurgear 886 is mounted onto the shaft of potentiometer 880 (FIG. 12H).Illustratively in FIG. 12I, the wires 1210 are connected (soldered) toexternal potentiometer 880 in the same arrangement they were removed inFIG. 9F (i.e. green/white=left, yellow=center, red=right). The servo 802is pushed up such that the servo gear 850 functionally connects to largespur gear 886, and screws 894 are tightened (FIG. 12J). FIG. 12Killustrates apparatus 800 assembled in accordance with FIGS. 12A-J. Itis important to note that apparatus 800 may be used in a variety ofdifferent applications. Based on requirements and availability ofcomponents, variations may be employed to the configuration of apparatus800 to achieve enhanced servo performance.

Although the present invention has been described with reference topreferred embodiments, workers skilled in the art will recognize thatchanges may be made in form and detail without departing from the spiritand scope of the invention.

1. A hobby servo motor device having enhanced operational capacity, thedevice comprising: a hobby servo motor having a rotatable servo splineand receiving a coded signal from an input line; a rotatable auxiliaryshaft displaced from and rotatably coupled to the servo spline; anauxiliary potentiometer functionally connected to the auxiliary shaft,the auxiliary potentiometer providing an output signal to the hobbyservo motor; and wherein an angular position of the auxiliary shaft isproportionally controlled based on the coded signal from the input lineand the auxiliary potentiometer output signal.
 2. The device of claim 1wherein the output signal comprises a left signal, a center signal, anda right signal.
 3. The device of claim 1 wherein the servo spline hasbetween 23 and 25 teeth.
 4. The device of claim 1 wherein the auxiliaryshaft is rotatably coupled to the servo spline comprises a servo splinegear coupled to an auxiliary shaft gear.
 5. The device of claim 4wherein the diameter of the servo spline gear is less than the diameterof the auxiliary shaft gear.
 6. The device of claim 4 wherein thediameter of the servo spline gear is greater than the diameter of theauxiliary shaft gear.
 7. The device of claim 1 and further comprising aframe that mounts the hobby servo motor and the auxiliary shaft.
 8. Thedevice of claim 1 and further comprising a mechanical load attached tothe auxiliary shaft.
 9. A hobby servo motor device having enhancedoperational capacity, the device comprising: a hobby servo motor havinga rotatable servo spline; a rotatable auxiliary shaft displaced from androtatably coupled to the servo spline; an auxiliary potentiometerfunctionally connected to the auxiliary shaft, the auxiliarypotentiometer providing an output signal to the hobby servo motor; and amechanical load attached to and actuated by the auxiliary shaft.
 10. Thedevice of claim 9 wherein the hobby servo motor receives a coded inputsignal.
 11. The device of claim 10 wherein the auxiliary potentiometeroutput signal and the coded input signal are utilized to position themechanical load.
 12. The device of claim 9 wherein the hobby servo motorand the auxiliary shaft are mounted in a frame.
 13. The device of claim12 wherein an axis of rotation of the servo spline and an axis ofrotation of the auxiliary shaft are parallel.
 14. The device of claim 13wherein the auxiliary shaft is rotatably coupled to the servo splinecomprises a servo spline gear coupled to an auxiliary shaft gear. 15.The device of claim 14 wherein the servo spline gear and the auxiliaryshaft gear are at least approximately coplanar.
 16. The device of claim15 wherein the servo spline has between 23 and 25 teeth.
 17. Anapparatus for enhancing the operation performance of a hobby servomotor, the apparatus comprising: a frame having an aperture configuredto mount a hobby servo motor; a rotatable auxiliary shaft mounted in theframe; an auxiliary potentiometer functionally connected to therotatable shaft, the auxiliary potentiometer generating an output signalbased on an angular position of the auxiliary shaft.
 18. The apparatusof claim 17 and further comprising a mechanical load attached to theauxiliary shaft.
 19. The apparatus of claim 17 and further comprising agear attached to the auxiliary shaft.
 20. The apparatus of claim 17 andfurther comprising a sprocket attached to the auxiliary shaft.